"Ye are the salt of the earth: but if the salt have lost its savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men."
Consider three elements of our text. First, the salt. Just as salt preserves, we ought to live in such a way that we have a preserving influence on society. The psalmist wrote, "The wicked shall be turned into hell, and all the nations that forget God" (Psalm 9:17). Just as salt produces thirst, we ought to live in such a way that our lives influence others to develop a thirst for righteousness (Matthew 5:6). Just as salt is used as a purifying agent, Christians are to be examples of purity in all we do. James wrote, "Pure religion and undefiled before God and the Father is this, To visit the fatherless and widows in their affliction, and to keep himself unspotted from the world" (James 1:27).
Second, consider the savour. Certain translations render this "flavor." But salt is a stable compound that does not lose its taste. When Jesus spoke of salt that had lost its savour, he was referring to salt that had lost its identifying characteristics. Salt loses its identifying characteristics when it becomes mixed with other elements and is no longer pure. When we as Christians become entangled in the sins of the world we fail to possess the identifying character traits expected of us as Christians. We lose our effectiveness in Christ's kingdom.
Third, consider the casting out. When salt loses its distinctiveness, it is good for nothing. It is cast out and is allowed to be trodden under by the foot of men. If we as Christians lose our savour we too will be cast out. Faithful Christians are commanded to withdraw their fellowship from the unfaithful (II Thessalonians 3:6, Titus 3:10). Ultimately, eternal separation will take place as those who are unfaithful will be cast into hell (Matthew 25:41, 46).